New Predictive Equations for the Specific and Apparent Molar Heat Capacities of Multicomponent Aqueous Solutions Conforming to the Linear Isopiestic Relation

Abstract

Abstract The linear isopiestic relation has been used together with well-known thermodynamic equations to establish new simple predictive equations for the specific and apparent molar heat capacities. These equations can provide predictions for multicomponent solutions conforming to the linear isopiestic relation using only information on the corresponding binary subsystems. No additional empirical parameters are involved. The predictive capabilities of the equations have been tested by comparing with the experimental specific or apparent molar heat capacities for the ternary systems (NaCl-NaNO3-H2O, NaCl-NaClO4-H2O, NaCl-KBr-H2O, NaCl-CaCl2-H2O, NaCl-MgCl2-H2O, and CaCl2-MgCl2-H2O) at 298.15 K and the reciprocal system (K-Na-Cl-SO4-H2O) at 373.15 K. The agreement is excellent over the entire experimental composition ranges.